title: Spatial modulation of second-harmonic generation via nonlinear Raman-Nath diffraction in an aperiodically poled lithium tantalite.
abstract: We propose and experimentally demonstrate a colorful nonlinear Raman-Nath second-harmonic generation by engineering the quadratic nonlinearity χ((2)) in an aperiodically poled lithium tantalite. The engineered nonlinear structure allows multicolored Raman-Nath second-harmonic signal outputs along a uniform direction, which cannot be achieved in a uniform nonlinear grating. The diffraction angles are independent of the beam waist and the position of incidence. This verifies that nonlinear Raman-Nath diffraction does not depend on the local superlattice structure where the fundamental frequency beam locates, but on the whole nonlinear χ((2)) crystal.
authors.affiliation: State Key Laboratory on Fiber Optic Local Area Communication Networks and Advanced Optical Communication Systems, Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China. ypchen@sjtu.edu.cn
authors.forename: Yuping
authors.initials: Y
authors.lastname: Chen
authors.forename: Weirui
authors.initials: W
authors.lastname: Dang
authors.forename: Yuanlin
authors.initials: Y
authors.lastname: Zheng
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Chen
authors.forename: Xuewei
authors.initials: X
authors.lastname: Deng